Contraceptive Hormones for Rodent Management

Presented by Steven Belmain, Professor of Ecology at the Natural Resources Institute, University of Greenwich, United Kingdom

About the Presenter

Steven Belmain is Professor of Ecology at the Natural Resources Institute, University of Greenwich, United Kingdom. Steve is a long-term advocate for ecologically-based rodent management, generating information on the impact of rodent pests on people’s livelihoods and health and developing sustainable methods of control without the use of poisons. This work is within a One Health framework that relies on multidisciplinary teams to understand environmental parameters and human behavior with a view to developing ways of changing behaviors that reduce risk of zoonotic spill-over, crop damage and stabilizing habitat biodiversity. Steve’s research on rodents was a key component of a Queen’s Anniversary Prize in 2019 for the University of Greenwich. His international research on rodents has led to him advising the World Health Organisation and governments of Bangladesh, Madagascar, Sierra Leone, Hong Kong, the Bahamas and Nepal on rodent borne disease outbreaks and rodent management. As some examples of his public engagement, Steve has starred in a nature documentary for the Discovery Channel Swarmchasers: Rats! with recent feature article on Global Health Security Rise of the rodent: Is the next pandemic brewing in rats?

The BIWFC hosted a webinar, “Contraceptive hormones for rodent management” featuring Steven Belmain, Professor of Ecology at the Natural Resources Institute, University of Greenwich, United Kingdom on February 16, 2023.

Hundreds of millions of rodents are killed each year in agricultural production and in our cities to prevent crop losses, food contamination and reduce disease impacts to livestock and human health. Compared to larger mammals targeted by fertility control programs, the prolific breeding and relatively short life span of rodents introduces different challenges and opportunities for the use of fertility control. However, prospects to increase use of fertility control for rodents are growing as regulators continue to restrict the use of poisons that are progressively perceived to be inhumane and negatively affecting environmental health.

Belmain’s research has focused on investigating whether contraceptive hormones are a feasible option for rodent management. Research initiated in China with the Institute of Zoology, Chinese Academy of Sciences showed that commonly used synthetic hormones levonorgestrel and quinestrol could reduce fertility in a range of rodent species. They could be effective against both sexes, particularly when combined together in a food bait. However, efficacy could vary differentially between males and females and with regards to the concentration and ratio of the two compounds for different rodent species.

Together with Chinese partners, Belmain’s work extended collaborations to Africa where more rodent species have been evaluated in laboratory and field trials. This work has helped to understand baseline physiological efficacy, duration of effect/reversibility, and how it works under field conditions. Tanzania has recently licensed a contraceptive bait for commercial use, and further work continues to understand potential non-target environmental impacts and efficacy in different contexts.